The First Animals to Move onto Land Were__________

question 61

Short Answer

The first animals to move onto land were__________ .

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Definitions:

Sex Chromosomes

The chromosomes (X and Y) responsible for determining the biological sex of an organism.

Spermarche

The beginning of development of sperm in boys’ testicles at puberty, marking the onset of adolescent fertility.

Testes

The male reproductive glands that produce sperm and the hormone testosterone.

XY

A chromosomal designation for male sex in many organisms, including humans, where males typically have one X and one Y chromosome.